Alert archive / Illinois / Mesoscale Discussions in 2021
Mesoscale Discussion 7
The Storm Prediction Center issued this mesoscale discussion at Jan 1, 2021, 6:35 AM CST for 4 states. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Jan 1, 2021, 6:35 AM CST (12:35 UTC)
- Expired
- Jan 1, 2021, 11:00 AM CST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Freezing rain
All 48 counties
Des Moines County, IA, Lee County, IA, Adams County, IL, Brown County, IL, Bureau County, IL, Cass County, IL, Champaign County, IL, DeWitt County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Iroquois County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, LaSalle County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Mercer County, IL, Morgan County, IL, Peoria County, IL, Piatt County, IL, Pike County, IL, Putnam County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Stark County, IL, Tazewell County, IL, Vermilion County, IL, Warren County, IL, Will County, IL, Woodford County, IL, Benton County, IN, Jasper County, IN, Lake County, IN, Newton County, IN, Warren County, IN, Lewis County, MO
The radar
The Lincoln radar (KILX), 58 km from the middle of the area, began a volume at 12:35 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Lincoln, IL (KILX), launched 12:00Z, 0.6 hours before the alert went out and 88 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1303 m above ground
- 0-6 km bulk shear
- 68 kt
- 0-1 km storm-relative helicity
- 177 m²/s²
- 0-3 km storm-relative helicity
- 324 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
598
ACUS11 KWNS 011235
SWOMCD
SPC MCD 011235
INZ000-ILZ000-IAZ000-MOZ000-011700-
Mesoscale Discussion 0007
NWS Storm Prediction Center Norman OK
0635 AM CST Fri Jan 01 2021
Areas affected...extreme northeast MO...southeast IA...central and
northern IL into northwest IN
Concerning...Freezing rain
Valid 011235Z - 011700Z
SUMMARY...Periods of moderate to heavy freezing rain will continue
across far northeast MO into central IL and parts of northwest IN
early this morning. Precipitation rates will increase across
northern IL over the next couple of hours.
DISCUSSION...A band of freezing rain, moderate to heavy at times,
will continue from far northeast MO into central IL and northwest IN
the next couple of hours. As the upper low over OK continues to
eject northeast this morning, a strong deformation zone will lift
northward across the northern IL vicinity. Meanwhile, strong warm
advection in the 850-700 mb layer will continue to support efficient
precipitation rates over a shallow near-surface cold layer around
26-32 degrees F. Freezing rain rates have been as high as 0.05
inches per hour for brief periods early this morning, but overall
rates of around 0.03-0.05 inches per 3 hour period are more
widespread. Some areas could see brief instances of snow or sleet
mixing with freezing rain, especially as the upper low tracks closer
to the region and midlevel temperatures cool sufficiently later this
morning toward midday.
..Leitman.. 01/01/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...IWX...IND...LOT...ILX...LSX...DVN...
LAT...LON 40439171 40899129 41119106 41429018 41618887 41608808
41588763 41458729 41248701 40998681 40578695 40268744
39918819 39728911 39539020 39659118 40029179 40279183
40439171SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jan 1, 1:08 AM CST | Mesoscale Discussion | SPC | Bond, Brown, Calhoun, Cass, Champaign, Christian and 43 more | 5 hr |
| Jan 1, 2:33 AM CST | Mesoscale Discussion | SPC | Adams, Brown, Calhoun, Cass, Greene, Jersey and 4 more | 5 hr |
| Dec 31, 8:44 PM CST | Mesoscale Discussion | SPC | Barry, Barton, Benton, Camden, Cedar, Christian and 35 more | 6 hr |
Nearby
Mesoscale Discussions in Illinois, 2021Mesoscale Discussions in Indiana, 2021Mesoscale Discussions in Iowa, 2021Every mesoscale discussion in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.